Electrical discharge device



P. K. DEVERS .ELECTRICAL DISCHARGE DEVICE Filed Dec. 27. 1926 Patented Aug. 30, 1927.

UNITED STATES PATENT orrica.

rmmr K. DIVERS, OI LYNN, MASSACHUSETTS, ABSIGNOB TO GENERAL ELECTRIC COMPANY, A CORPORATION OF NEW YORK.

ELECTRICAL DISCHARGE DEVICE.

Application fled December 87, 1826. Serial no. 157,080.

The present invention relates to the class of electric discharge devices which operate b ionization of gas or vapor and in'whlch tile initially high electric resistance must be broken down, as for example, by an auxiliary discharge, before a discharge will operate between the main electrodes at the normal operating potential. It is the object of my invention to provide an improved starting arrangement.

In U. S. Patent 1,306,559 issued to John Orange on .June 10, 1919, is described an arc device, containing electrodes supporting an are at incandescence in mercury vapor. The arc is started in an auxiliary circuit containing a body of mercury. Some of the mercury 1s evaporated when a starting current is caused to flow, thereby breaking the continuity of the auxiliary circuit and starting an auxiliary arc discharge which in turn starts the main discharge.

It is difficult to admit the exact amount of.

mercury to such a device which is required to complete the starting circuit when the deas vice is not operating without introducing even a slight excess of mercury so that the circuit ma be readily broken by evaporation of t e mercury. Small globules of mercury forming b condensation on the so walls of the device d ilring its operation also may unduly deplete the mercury in the startin circuit. For this reason the device, may fail to restart after an interruption because the starting circuit remains open-circuited. 3 In accordance with my present invention these difiiculties are overcome by roviding in the envelo a small receptac e or cup suitably positioned with respect to the starting circuit and in which suflicient and definite amount of mercury may be introduced to positively complete the startingcircult, By properly proportioning and positioning this receptacle, the amount of mercury thus introduced into the starting circuit can be (I restricted to an amount which will not unduly delay the starting of the arc.

My invention is illustrated in the accompanyin drawing in which Fig. 1 is a side view 0 my improved device prior to starting the arc (the main envelope being shown in part broken away) view of the device after operation.

Referring to the drawing, the device comprises an envelope 1 consisting of glass quartz or other suitable material. Sealed in Fig. 1 terminate in electrodes 6, '7 consist- .sequently the starting of the main discharge andFig. 2 is a side therein are stems or wires 2,3 consisting of tungsten, molybdenum or .other suitable metal. The ends 4:, 5 of these stems, which preferably are reduced in section as shown ing of tungsten or other suitable refractory material, these electrodes being separated by a gap havingqa length of 15 to 500 mils, depending on t e character ofthe device. The space within the envelope may be evacuated or charged with a suitable gas, such as nitrogen, hydrogen, a rare gas, such as argon, or a mixture of gases. There also is contained therein a quantity 8 of mercury, or other suitable normally liquid, easily vaporizable material. Depending from the conductors 4, 5 and joined thereto as by. fusion, are small spiral conductors 10, 11 which terminate in electrode-like enlargements or terminals 12, 13. These terminals 12, 13 project into a cup 14, which preferably consists of silica and which is aflixed to the envelope 1 at 15. In a 200 watt device the main electrodes 6, 7 may have a diameter of about 100 mils. The coils 10, 11 may consist of 18 mil wire wound on a 40 mil mandrel and may have 8 to 10 turns.

7 When it is desired to start an are between the main electrodes 6, 7 a globule of mercur 16 is introduced into the cup 14 by sha ing or tilting the device. Thereby completing the starting circuit, current is caused to flow in the starting circuit evaporatinglsome of the mercury andagain breaking t e circuit and starting an arc which travels up the coils and establishes an are between the main electrodes. The resistance of the coils is chosen to be greater than the resistance of the main discharge path. Conis prompt and positive. When the mercury globule 16 is removed by evaporation from the cup 14 it lodges in the. space between the cup and the envelope 1 and hence can not interfere with the steady operation on the are.

What I claim as new and desire to secure by Letters Patent of the United States, is:

1. An electric discharge device comprising an envelope, cooperating spaced electrodes therein, a starting circult therefor, a quantity of normally liquid vaporizable conducting material in said envelope, and a receptacle within said envelope located and shaped to contain a quantity of said vaporiz- I.

able material in position to close said starting circuit.

2. An electric discharge device comprising an envelope, cooperating fixed electrodes therein constituted of substantially nonvaporizable material, a normally incomplete starting circuit therefor, a quantity of mercury in said envelope, and means in sa1d envelope facilitating the introduction into said starting circuit of a definite amount of mercury to complete said starting circuit.

3. An electric discharge device comprising an elongated envelope, conducting stems sealed into one end of said envelope and extending to a region adjacent the opposite end PHILIP K. DEVERS. 

